Post on 25-Mar-2018
Teeth selection for edentulous and partially edentulous patients
Balqees almufleh
BDS, Certi (Prosth), MSc
• Artificial teeth selection for complete denture
Anterior teeth selection
Posterior teeth selection
• Artificial teeth selection for removable partial denture
Anterior teeth
Posterior teeth
One of the objectives of complete denture prosthetics is to produce a
harmonious appearance of the denture when in the patient’s
mouth A denture is usually perceived esthetic
when the teeth and bases are in harmony with the facial musculature as well as the size and shape of the head
Selection of the anterior teeth
• Study casts:
They are the most reliable guides in selecting the size, shape and position of the natural
Selection of the anterior teeth
• Photographs:
Helps in determining the placement of teeth, arch form, lip support than the actual size or shape of teeth
Use close up photo
Use the most recent
Selection of the anterior teeth
• Intra-oral radiographs:
Can supply information about width, length and shape of teeth
May be distorted??
Selection of the anterior teeth
• Extracted teeth:
Can supply information about size and mold of teeth
colour??
Selection of anterior teeth
Guides for selection of
Size
Width MD
Length OG
Thickness BL
Form or shape
shade
Selection of anterior teeth
Guides for selection of teeth
width
Bizygomatic width
BL centers of
hamular notch
Corners of mouth
Lateral surfaces of nose
Cranial circumfer
ence
Ridge size and
contour
Incisive papilla
WIDTH
• Post extraction guides to determine width:
Bi zygomatic width
Combined width of six maxillary anterior may be estimated by dividing the maximum bizygomatic width of skull by 3.3
The width of maxillary central incisor may be estimated by diving the maximum bizygomatic width by 16
WIDTH
• Post extraction guides to determine width:
Buccolingual centers of hamular notches
Combined width of six maxillary anterior equals the distance between the buccolingual centers of hamular notches plus 5 mm
WIDTH
• Post extraction guides to determine width:
Corners of the mouth
The distal surface of many natural upper canines is positioned at the corner of the relaxed mouth
WIDTH
• Post extraction guides to determine width:
Canine eminence
If it is well defined, the distance between lines drawn on the master cast of the upper jaw at the distal aspect of the eminence may be taken as the mesiodistal width of the six anterior teeth
WIDTH
• Post extraction guides to determine width:
Width of nose
Distance between lateral extremities of the ala of nose can be measured with dividers and then transferred to the occlusion rims
Approximately 6 mm should be added to give the width of the six anterior teeth
Clinical way…. Pic?
WIDTH
• Post extraction guides to determine width:
Size and contour of residual ridge
The growth of alveolar bone requires presence and eruption of teeth. Therefore the size of residual ridges on casts have a relationship to size of anterior teeth
Bone resorption after extraction will result in loss of contour and incorrect choice
• Post extraction guides to determine width:
Size and contour of residual ridge
Pattern of alveolar bone loss after extraction
Maxilla: ant. Vertical and palatal direction
Post. Vertical and medial direction
Mandible: ant. Vertical and lingual direction
Post. Vertical and slight lingual direction
• Post extraction guides to determine width:
Lateral surface of the nose
Imaginary line through the lateral surface of nose and the center of brow line will indicate the distal aspect of the canine tooth at the point where the projected line passes through the occlusal plane
• Post extraction guides to determine width:
The Incisive papilla
Imaginary transverse line bisecting the incisive papilla will pass through the middle of the upper canines
• Post extraction guides to determine width:
Maxillomandibular relation
Any disproportion in size between the maxillary and mandibular arches influences length, width and position of teeth
• Post extraction guides to determine width:
Cranial circumference
The horizontal circumference of the cranium at a plane passing through the glabella and maximum occipital point is said to be 10 times the width of the maxillary anterior teeth
LENGTH
• Post extraction guides to determine length:
Vertical distance between the ridges
Length of teeth is determined by the available space between the alveolar ridges
• Post extraction guides to determine length:
The lips:
Length of anterior teeth can be determined from relaxing lips
Amount of central incisor visible below the lip when lip is relaxed and teeth apart is about 2-3 in young people and less in older individuals
When teeth are in occlusion lower lip is supported by incisal third of upper central incisor
• Post extraction guides to determine length:
The lips:
On smiling amount of tooth show is related to:
1. Length of upper lip
2. Mobility of upper lip
3. Vertical dimension of occlusion
4. Vertical overlap of teeth
THICKNESS
• Post extraction guides to determine thickness:
Thickness of teeth has a considerable effect on phonetics as well as esthetics
SHAPE/ FORM
• Post extraction guides to determine shape of anterior teeth:
1. Shape of the arch
There is a relation between the shape of the upper arch and incisor teeth.
It may be square, tapering and ovoid
• Post extraction guides to determine shape of anterior teeth:
2. Shape of the face
Leon Williams classification
The shape of the upper central incisor usually coincide with the inverted form of the face
It may be square, tapering or ovoid
• Post extraction guides to determine shape of anterior teeth:
2. Shape of the face
Leon Williams classification
The shape of the upper central incisor usually coincide with the inverted form of the face
Basic facial forms: square, tapering square, tapering and ovoid
• Post extraction guides to determine shape of anterior teeth:
2. Shape of the face
The outline form or shape of the anterior teeth should harmonize with the shape of the patient’s face
• Post extraction guides to determine shape of anterior teeth:
2. Shape of the face
Trubyte indicator is used of determination of the facial outline
The form of the face is observed by noting the outline form as it appears in comparison with the vertical lines of the tooth indicator
• Post extraction guides to determine shape of anterior teeth:
2. Shape of the face
It is helpful in observing the relative straightness or curvature of the profile
The forehead, the base of the nose and the point of the chin should be checked
If the three points are in line the profile is straight
If the three points are recessive, the profile is curved
• Post extraction guides to determine shape of anterior teeth:
3. Sex
Curved facial features are associated with femininity and square features are associated with masculinity
Ovoid tooth is more feminine and square tooth is more masculine
Curved labial surface is more feminine and a flat labial surface is more masculine
• Post extraction guides to determine shape of anterior teeth:
4. Age
With age incisal edges and interproximal surfaces wear
Labial surfaces seem flatter and the outline form appears more square
SHADE
• Post extraction guides to determine shade:
Patient’s age
Dark teeth are more suitable for old patients while lighter teeth are more suitable for younger
• Post extraction guides to determine shade: Must be in harmony with the surrounding
environment Patient’s skin colour Light teeth for fair skin, blue eyes dark teeth usually for dark skin and eyes Maxillary central incisor are the lightest teeth in the
mouth, maxillary laterals and lower incisors are slightly darker, canines are darker
Mandibular anterior teeth
Each set of upper anterior teeth has a corresponding set of lower anterior teeth which matches it in
• Size
• Form
• color
Mandibular anterior teeth
Exceptions:
When selecting teeth for class II anterior teeth relationship, use mandibular teeth smaller and lighter in shade than that recommended by the mould guide
because of retruded and narrow mandibular arch the space is less…. Narrower
Lighter shade creates illusion that teeth are more anterior than they really are
Mandibular anterior teeth
Exceptions:
When selecting teeth for class III anterior teeth relationship, use mandibular teeth larger and less brilliant than that recommended by the mould guide
because of protruded and wider mandibular arch providing more space…. Larger teeth
Less brilliant teeth so they do not look as brighter
Dentogenic concept
Introduced by Frush and Fisher in mid-1950s
Based on patient’s age, sex and personality
Old, male, smokers with bold vigorous personality tend to have darker teeth
Female with delicate personality….lighter shade
Dentogenic concept
It advices dentists to select, arrange and alter teeth, carve the gingiva according to the patient’s age, sex and personality
Posterior teeth selection
Factors for consideration when selecting posterior teeth:
Ridge morphology
Interarch distance
Arch relationship
Patient’s age and neuromuscular control
Esthetics
Comminution of food
Previous denture wearing experience
Posterior teeth selection
It is more empirical than anterior teeth selection
• The shade should harmonize with that of anterior especially premolars
• SIZE:
Posteriors should have smaller mesiodistal width to minimize stresses on supporting structures, increases the tongue space and improves the shape of the polished surface
Posterior teeth selection
It is more empirical than anterior teeth selection
• The mesiodistal width is determined by the length and slope of mandibular ridge
- Different ridge relation
- Measurement of the mesiodistal space from the distal of the canine to the mesial end of the retromolar pad
Posterior teeth selection
It is more empirical than anterior teeth selection
• The length is determined by the interarch distance
• The thickness (BL width) less than natural teeth
Decrease stresses and provide a space for tongue and polished surfaces of denture
Should provide enough support to the cheek
Posterior teeth selection
Selection of teeth form:
Anatomic teeth- 33 degrees teeth
Simulate natural teeth
Suitable for young healthy patients with good ridges
Used with balanced occlusion
Posterior teeth selection
Selection of teeth form:
Non Anatomic teeth- 0 degrees teeth
Have flat occlusal surface
Not efficient unless provided with cutting ridges, spillways
Transmit less destructive forces to the tissues
Suitable for old patients having poor ridges, and poor neuromuscular control, abnormal jaw relation or corssbites
Posterior teeth selection
Selection of teeth materials: Esthetics Color stability Wear Adjustment Transmission of forces Polishing Bonding Fracture Repair Noise during use
Anterior teeth selection for RPD
Important for esthetic and incising food
Best arranged when patient is present
Anterior teeth selection for RPD
When selecting denture teeth, the practitioner should use the shade guide provided by the tooth manufacture
Anterior teeth selection for RPD
Artificial teeth should be matched as closely as possible to the adjacent natural teeth or fixed restorations
The matching process should be accomplished using natural light and should be completed as quickly as possible
Anterior teeth selection for RPD
Mold selection is based upon two important factors:
• The space that has been created by tooth loss
• Overall form or shape of the teeth
Anterior teeth selection for RPD
Mold selection is based upon two important factors:
• The space that has been created by tooth loss
• Overall form or shape of the teeth
By determining the shape of the patient’s face you choose the appropriate form for the anterior teeth
Anterior teeth selection for RPD
Denture teeth on a denture base generally permit the most esthetic results. In such a situation, the denture base may be built to provide the appropriate support and contour for the lips
Anterior teeth selection for RPD
If maxillary central incisors are missing. It is essential that these teeth be set first. This allows the practitioner to reestablish the maxillary midline in the center of the face
Anterior teeth selection for RPD
If an anterior denture tooth is to be positioned against a natural tooth, the proximal surface of the prosthetic tooth must be contoured to permit close adaptation
Selective recontoring of axial and incisal surfaces permits improved adaptation and appearance
Anterior teeth selection for RPD
The denture base flanges should be contoured and smoothed to provide a pleasing appearances
During the try-in appointment the practitioner should seek feedback regarding tooth arrangement
Posterior teeth selection for RPD
materials:
Improved acrylic resin teeth with gold occlusal surfaces are preferabbly used in opposition to natural teeth restored with gold occlusal surfaces
Posterior teeth selection for RPD
materials:
Porcelain teeth are generally used in opposition to other porcelain teeth
Posterior teeth selection for RPD
Posterior teeth must fit into available edentulous spaces and in harmony with opposing occlusal surfaces
Posterior teeth selection for RPD
Tooth size is determined by the length of the edentulous space
In distal extension, tooth size is determined by the sizes of the opposing teeth as well as the length of the edentulous space
Posterior teeth selection for RPD
Tooth size is determined by the length of the edentulous space
When removable partial denture is opposed by a complete denture, the practitioner measures from the distal surface of a natural canine to the incline of the ramus in the mandibular arch
Posterior teeth selection for RPD
Tooth size is determined by the length of the edentulous space
When removable partial denture is opposed by a complete denture, the practitioner measures from the distal surface of a natural canine to the incline of the ramus in the mandibular arch
Posterior teeth selection for RPD
The occlusoginigval height of each replaced tooth must be considered
Most posterior teeth are available in short, medium and long